This invention relates to a spinning machine having spinning stations arranged on both sides of the machine for the spinning of yarns from slivers which are fed to the spinning stations in cans deposited above the spinning machine, guiding devices for the slivers being arranged between the cans and the spinning stations.
The feeding of the fiber material to be spun in the form of slivers disposed in cans is known, for example, in the case of open-end spinning machines. In the case of the commercially available machines, the slivers are withdrawn directly by the sliver feeding device of the individual spinning stations from the cans standing in front of and partially below the spinning arrangement.
It is also known (German Patent Document DE-C 23 35 740), in the case of open-end spinning machines, to arrange the cans on a platform above the spinning machine and to feed the slivers through guiding tubes to the spinning stations. These guiding tubes, which are equipped with baffles, are to be used as an intermediate storage device which, because of a special construction, is fed by a continuously running feeding device nevertheless intermittently. The sliver should then be guided through the respective guiding tube essentially free of tensile stress.
The feeding of fiber material in the form of slivers made available in cans is also known in the case of other fast running spinning machines, for example, in the case of wind-around spinning machines or air spinning machines. As a rule, these are one-sided machines, in which the slivers, which were withdrawn from the cans deposited on the rear of the spinning machine, are fed from above to the spinning stations. In this case, guiding devices are provided in the form of rollers and guide rods for the slivers.
It is also known (German Patent Document DE-PS 817 572), in the case of ring spinning machines, to feed slivers in cans which are deposited on platforms or in a space above the spinning machine. In this case, relatively long paths with one or several vertical runs are obtained which lead to the risk that the slivers may hang out; that is, are drafted uncontrollably because of their own weight. Such an arrangement is therefore possible only for slivers which have a relatively coarse size and thus a relatively high stability.
However, the spinning of slivers of relatively coarse sizes is very difficult on ring spinning machines. Since the ring spinning machines have only a relatively low delivery speed at the outlet of the drafting units,--taking into account the required draft--the feeding rollers of the drafting units must run very slowly; that is, at rotational speeds of one revolution per minute and less. It is technically very difficult to let long shafts, like the feeding rollers of drafting units, run at such low rotational speeds with sufficient precision. There is the risk that these shafts will rotate only jerkily so that no controlled draft is obtained. The feeding of the fiber material to be spun in cans has therefore not been carried out successfully in practice in the case of ring spinning machines.
In related U.S. copending applications Ser. No. 809,141, filed Dec. 18, 1991 and Ser. No. 948,638, filed Sep. 23, 1992 it is suggested to provide transport belts as guiding devices which interact with one skid respectively. The skids extend in the area of the center plane of the spinning machine in the vertical direction and each have a curvature in the direction to the downward travelling runs of the transport belts. The skids abut at their respective ends and are mutually supported there.
It is an object of the invention to develop a spinning machine of the initially mentioned type in such a manner that also fine slivers may be fed in cans without the risk of faulty drafts, particularly in vertical runs of the transport path.
This object is achieved in that the guiding devices, in the area of the center plane of the spinning machine, comprise skids which are arranged vertically and spaced from one another, are assigned to one side of the machine respectively and are pressed apart in the manner of a fishbelly or convex curved shaped by means of spreader devices, and in that a transport belt is assigned to each skid which is in close contact with the respective associated skid and transports one or several slivers.
In the case of the development according to the invention, it is achieved that the slivers are supported and are nevertheless moved in the transport direction. As a result, it is possible to feed also relatively thin slivers in cans; that is, slivers of sizes of approximately Nm 0.4 to 0.8. In this case, these fine slivers may also be transported in the vertical direction along larger runs. It is therefore possible to carry out a can feeding also in the case of ring spinning machines because, on the basis of the slivers with the fine sizes, while taking into account the draft, the feeding roller pairs of the drafting units still run at a sufficiently high speed so that a uniform round rotating is ensured. By means of this can feeding, it will then be possible, in the case of ring spinning machines, to do without a premounted machine, specifically the flyer. In the case of other spinning machines, which are equipped with drafting units into which the slivers travel, it is possible to feed finer slivers so that then the drafting units may be simplified. For example, in the case of machines of this type, there is the possibility to use, instead of five-cylinder drafting units, the three-cylinder drafting units which are customary today in the case of ring spinning machines.
Also in the case of open-end machines, the feeding of finer slivers results in advantages because then the opening-up work for the separating of the fibers is reduced so that, during the opening-up, the fibers are processed more carefully. It is therefore possible to spin finer yarns with less damaged fibers so that the yarns have a higher quality.
The pressing-apart of the skids in the manner of a fishbelly caused by the spreader devices has the result that the transport belts establish a soft contact. In this case, the spreader devices are arranged approximately in the center in the case of skids of a length of approximately two meters. In the center of the skids, the bulging-out is the most pronounced; it is the least pronounced on the very top and on the very bottom. The "fishbelly" is only very slight. In the area of the deflection rollers of the transport belts, the skids must not be supported by spreader devices so that they can spring there freely and are sufficiently soft.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.